Tetrahedral structures in general are shown in U.S. Pat. Nos. 3,221,464 and 4,521,998. Collapsible types of such structures can be seen in U.S. Pat. Nos. 3,486,279; 4,069,832; 4,393,887; 4,539,786; and 4,569,176. Specific of such units that are deployable in outer space are illustrated in for example, U.S. Pat. Nos. 4,337,560; 4,527,362; and 4,557,097. Of particular relevance to the present invention however is that structure illustrated and described in U.S. Pat. No. 4,579,302. However, none of these prior art references disclose or suggest the novel thermal compensating connector system of the present invention which allows for expansion and contraction between the truss of a space station and a foldable expandable pallet. This compensating feature of the present invention also takes into account any inherent manufacturing inaccuracies that may be present which would hinder the use of a particular component after it has been stowed and transported into outer space. Such hindrances must be avoided because limited payloads cannot afford such a luxury. The foregoing prior art references further fail to disclose or suggest the novel design of the present invention of a yoke-like node point fitting nor do they suggest the use of a foldable expandable pallet as a rotary joint transition piece, in the servicing of space station rotary joints, and as a roadbed, for example.
Much of the prior art has involved space stations having as a necessity node points that are closely spaced and this type of construction has created undesired flexural and torsional deflections resulting in severe control problems.
The expense of past units has been extreme and due to their large size resulted in bulky loads in the payload bay adding to the number of orbiter flights. The foldable expandable pallet of the present invention however, removes the constraint that the main structure must have closely spaced node points for attachment purposes. Thus, there is provided a structure that has widely spaced node points and yet is stiff and structurally effective. The foldable expandable pallets of the present invention also possess the advantage that they can be expanded in orbit rather than assembled as in the case of much of the prior art.